Backport PR #9848: Allow to pass a pygments class to highlighting_style.

Fixes https://github.com/ipython/ipython/issues/9749.

IPython/terminal/interactiveshell.py

@@ -1,488 +1,493 b''
 """IPython terminal interface using prompt_toolkit"""
 from __future__ import print_function
 
 import os
 import sys
 import warnings
 from warnings import warn
 
 from IPython.core.interactiveshell import InteractiveShell, InteractiveShellABC
 from IPython.utils import io
-from IPython.utils.py3compat import PY3, cast_unicode_py2, input
+from IPython.utils.py3compat import PY3, cast_unicode_py2, input, string_types
 from IPython.utils.terminal import toggle_set_term_title, set_term_title
 from IPython.utils.process import abbrev_cwd
-from traitlets import Bool, Unicode, Dict, Integer, observe, Instance, Type, default, Enum
+from traitlets import Bool, Unicode, Dict, Integer, observe, Instance, Type, default, Enum, Union
 
 from prompt_toolkit.enums import DEFAULT_BUFFER, EditingMode
 from prompt_toolkit.filters import (HasFocus, Condition, IsDone)
 from prompt_toolkit.history import InMemoryHistory
 from prompt_toolkit.shortcuts import create_prompt_application, create_eventloop, create_prompt_layout, create_output
 from prompt_toolkit.interface import CommandLineInterface
 from prompt_toolkit.key_binding.manager import KeyBindingManager
 from prompt_toolkit.layout.processors import ConditionalProcessor, HighlightMatchingBracketProcessor
 from prompt_toolkit.styles import PygmentsStyle, DynamicStyle
 
 from pygments.styles import get_style_by_name, get_all_styles
+from pygments.style import Style
 from pygments.token import Token
 
 from .debugger import TerminalPdb, Pdb
 from .magics import TerminalMagics
 from .pt_inputhooks import get_inputhook_func
 from .prompts import Prompts, ClassicPrompts, RichPromptDisplayHook
 from .ptutils import IPythonPTCompleter, IPythonPTLexer
 from .shortcuts import register_ipython_shortcuts
 
 DISPLAY_BANNER_DEPRECATED = object()
 
 
 from pygments.style import Style
 
 class _NoStyle(Style): pass
 
 
 
 _style_overrides_light_bg = {
             Token.Prompt: '#0000ff',
             Token.PromptNum: '#0000ee bold',
             Token.OutPrompt: '#cc0000',
             Token.OutPromptNum: '#bb0000 bold',
 }
 
 _style_overrides_linux = {
             Token.Prompt: '#00cc00',
             Token.PromptNum: '#00bb00 bold',
             Token.OutPrompt: '#cc0000',
             Token.OutPromptNum: '#bb0000 bold',
 }
 
 
 
 def get_default_editor():
     try:
         ed = os.environ['EDITOR']
         if not PY3:
             ed = ed.decode()
         return ed
     except KeyError:
         pass
     except UnicodeError:
         warn("$EDITOR environment variable is not pure ASCII. Using platform "
              "default editor.")
 
     if os.name == 'posix':
         return 'vi'  # the only one guaranteed to be there!
     else:
         return 'notepad' # same in Windows!
 
 # conservatively check for tty
 # overridden streams can result in things like:
 # - sys.stdin = None
 # - no isatty method
 for _name in ('stdin', 'stdout', 'stderr'):
     _stream = getattr(sys, _name)
     if not _stream or not hasattr(_stream, 'isatty') or not _stream.isatty():
         _is_tty = False
         break
 else:
     _is_tty = True
 
 
 _use_simple_prompt = ('IPY_TEST_SIMPLE_PROMPT' in os.environ) or (not _is_tty)
 
 class TerminalInteractiveShell(InteractiveShell):
     space_for_menu = Integer(6, help='Number of line at the bottom of the screen '
                                                   'to reserve for the completion menu'
                             ).tag(config=True)
 
     def _space_for_menu_changed(self, old, new):
         self._update_layout()
 
     pt_cli = None
     debugger_history = None
     _pt_app = None
 
     simple_prompt = Bool(_use_simple_prompt,
         help="""Use `raw_input` for the REPL, without completion, multiline input, and prompt colors.
 
             Useful when controlling IPython as a subprocess, and piping STDIN/OUT/ERR. Known usage are:
             IPython own testing machinery, and emacs inferior-shell integration through elpy.
 
             This mode default to `True` if the `IPY_TEST_SIMPLE_PROMPT`
             environment variable is set, or the current terminal is not a tty.
 
             """
             ).tag(config=True)
 
     @property
     def debugger_cls(self):
         return Pdb if self.simple_prompt else TerminalPdb
 
     confirm_exit = Bool(True,
         help="""
         Set to confirm when you try to exit IPython with an EOF (Control-D
         in Unix, Control-Z/Enter in Windows). By typing 'exit' or 'quit',
         you can force a direct exit without any confirmation.""",
     ).tag(config=True)
 
     editing_mode = Unicode('emacs',
         help="Shortcut style to use at the prompt. 'vi' or 'emacs'.",
     ).tag(config=True)
 
     mouse_support = Bool(False,
         help="Enable mouse support in the prompt"
     ).tag(config=True)
 
-    highlighting_style = Unicode('legacy',
-            help="The name of a Pygments style to use for syntax highlighting: \n %s" % ', '.join(get_all_styles())
+    highlighting_style = Union([Unicode('legacy'), Type(klass=Style)],
+        help="""The name or class of a Pygments style to use for syntax
+        highlighting: \n %s""" % ', '.join(get_all_styles())
     ).tag(config=True)
 
     
     @observe('highlighting_style')
     @observe('colors')
     def _highlighting_style_changed(self, change):
         self.refresh_style()
 
     def refresh_style(self):
-        self._style = self._make_style_from_name(self.highlighting_style)
+        self._style = self._make_style_from_name_or_cls(self.highlighting_style)
 
 
     highlighting_style_overrides = Dict(
         help="Override highlighting format for specific tokens"
     ).tag(config=True)
 
     true_color = Bool(False,
         help=("Use 24bit colors instead of 256 colors in prompt highlighting. "
               "If your terminal supports true color, the following command "
               "should print 'TRUECOLOR' in orange: "
               "printf \"\\x1b[38;2;255;100;0mTRUECOLOR\\x1b[0m\\n\"")
     ).tag(config=True)
 
     editor = Unicode(get_default_editor(),
         help="Set the editor used by IPython (default to $EDITOR/vi/notepad)."
     ).tag(config=True)
 
     prompts_class = Type(Prompts, help='Class used to generate Prompt token for prompt_toolkit').tag(config=True)
 
     prompts = Instance(Prompts)
 
     @default('prompts')
     def _prompts_default(self):
         return self.prompts_class(self)
 
     @observe('prompts')
     def _(self, change):
         self._update_layout()
 
     @default('displayhook_class')
     def _displayhook_class_default(self):
         return RichPromptDisplayHook
 
     term_title = Bool(True,
         help="Automatically set the terminal title"
     ).tag(config=True)
 
     display_completions = Enum(('column', 'multicolumn','readlinelike'), 
         help= ( "Options for displaying tab completions, 'column', 'multicolumn', and "
                 "'readlinelike'. These options are for `prompt_toolkit`, see "
                 "`prompt_toolkit` documentation for more information."
                 ),
         default_value='multicolumn').tag(config=True)
 
     highlight_matching_brackets = Bool(True,
         help="Highlight matching brackets .",
     ).tag(config=True)
 
     @observe('term_title')
     def init_term_title(self, change=None):
         # Enable or disable the terminal title.
         if self.term_title:
             toggle_set_term_title(True)
             set_term_title('IPython: ' + abbrev_cwd())
         else:
             toggle_set_term_title(False)
 
     def init_display_formatter(self):
         super(TerminalInteractiveShell, self).init_display_formatter()
         # terminal only supports plain text
         self.display_formatter.active_types = ['text/plain']
 
     def init_prompt_toolkit_cli(self):
         if self.simple_prompt:
             # Fall back to plain non-interactive output for tests.
             # This is very limited, and only accepts a single line.
             def prompt():
                 return cast_unicode_py2(input('In [%d]: ' % self.execution_count))
             self.prompt_for_code = prompt
             return
 
         # Set up keyboard shortcuts
         kbmanager = KeyBindingManager.for_prompt()
         register_ipython_shortcuts(kbmanager.registry, self)
 
         # Pre-populate history from IPython's history database
         history = InMemoryHistory()
         last_cell = u""
         for __, ___, cell in self.history_manager.get_tail(self.history_load_length,
                                                         include_latest=True):
             # Ignore blank lines and consecutive duplicates
             cell = cell.rstrip()
             if cell and (cell != last_cell):
                 history.append(cell)
 
-        self._style = self._make_style_from_name(self.highlighting_style)
+        self._style = self._make_style_from_name_or_cls(self.highlighting_style)
         style = DynamicStyle(lambda: self._style)
 
         editing_mode = getattr(EditingMode, self.editing_mode.upper())
 
         self._pt_app = create_prompt_application(
                             editing_mode=editing_mode,
                             key_bindings_registry=kbmanager.registry,
                             history=history,
                             completer=IPythonPTCompleter(shell=self),
                             enable_history_search=True,
                             style=style,
                             mouse_support=self.mouse_support,
                             **self._layout_options()
         )
         self._eventloop = create_eventloop(self.inputhook)
         self.pt_cli = CommandLineInterface(
             self._pt_app, eventloop=self._eventloop,
             output=create_output(true_color=self.true_color))
 
-    def _make_style_from_name(self, name):
+    def _make_style_from_name_or_cls(self, name_or_cls):
         """
         Small wrapper that make an IPython compatible style from a style name
 
         We need that to add style for prompt ... etc. 
         """
         style_overrides = {}
-        if name == 'legacy':
+        if name_or_cls == 'legacy':
             legacy = self.colors.lower()
             if legacy == 'linux':
                 style_cls = get_style_by_name('monokai')
                 style_overrides = _style_overrides_linux
             elif legacy == 'lightbg':
                 style_overrides = _style_overrides_light_bg
                 style_cls = get_style_by_name('pastie')
             elif legacy == 'neutral':
                 # The default theme needs to be visible on both a dark background
                 # and a light background, because we can't tell what the terminal
                 # looks like. These tweaks to the default theme help with that.
                 style_cls = get_style_by_name('default')
                 style_overrides.update({
                     Token.Number: '#007700',
                     Token.Operator: 'noinherit',
                     Token.String: '#BB6622',
                     Token.Name.Function: '#2080D0',
                     Token.Name.Class: 'bold #2080D0',
                     Token.Name.Namespace: 'bold #2080D0',
                     Token.Prompt: '#009900',
                     Token.PromptNum: '#00ff00 bold',
                     Token.OutPrompt: '#990000',
                     Token.OutPromptNum: '#ff0000 bold',
                 })
             elif legacy =='nocolor':
                 style_cls=_NoStyle
                 style_overrides = {}
             else :
                 raise ValueError('Got unknown colors: ', legacy)
         else :
-            style_cls = get_style_by_name(name)
+            if isinstance(name_or_cls, string_types):
+                style_cls = get_style_by_name(name_or_cls)
+            else:
+                style_cls = name_or_cls
             style_overrides = {
                 Token.Prompt: '#009900',
                 Token.PromptNum: '#00ff00 bold',
                 Token.OutPrompt: '#990000',
                 Token.OutPromptNum: '#ff0000 bold',
             }
         style_overrides.update(self.highlighting_style_overrides)
         style = PygmentsStyle.from_defaults(pygments_style_cls=style_cls,
                                             style_dict=style_overrides)
 
         return style
 
     def _layout_options(self):
         """
         Return the current layout option for the current Terminal InteractiveShell
         """
         return {
                 'lexer':IPythonPTLexer(),
                 'reserve_space_for_menu':self.space_for_menu,
                 'get_prompt_tokens':self.prompts.in_prompt_tokens,
                 'get_continuation_tokens':self.prompts.continuation_prompt_tokens,
                 'multiline':True,
                 'display_completions_in_columns': (self.display_completions == 'multicolumn'),
 
                 # Highlight matching brackets, but only when this setting is
                 # enabled, and only when the DEFAULT_BUFFER has the focus.
                 'extra_input_processors': [ConditionalProcessor(
                         processor=HighlightMatchingBracketProcessor(chars='[](){}'),
                         filter=HasFocus(DEFAULT_BUFFER) & ~IsDone() &
                             Condition(lambda cli: self.highlight_matching_brackets))],
                 }
 
     def _update_layout(self):
         """
         Ask for a re computation of the application layout, if for example ,
         some configuration options have changed.
         """
         if self._pt_app:
             self._pt_app.layout = create_prompt_layout(**self._layout_options())
 
     def prompt_for_code(self):
         document = self.pt_cli.run(
             pre_run=self.pre_prompt, reset_current_buffer=True)
         return document.text
 
     def enable_win_unicode_console(self):
         import win_unicode_console
 
         if PY3:
             win_unicode_console.enable()
         else:
             # https://github.com/ipython/ipython/issues/9768
             from win_unicode_console.streams import (TextStreamWrapper,
                                  stdout_text_transcoded, stderr_text_transcoded)
 
             class LenientStrStreamWrapper(TextStreamWrapper):
                 def write(self, s):
                     if isinstance(s, bytes):
                         s = s.decode(self.encoding, 'replace')
 
                     self.base.write(s)
 
             stdout_text_str = LenientStrStreamWrapper(stdout_text_transcoded)
             stderr_text_str = LenientStrStreamWrapper(stderr_text_transcoded)
 
             win_unicode_console.enable(stdout=stdout_text_str,
                                        stderr=stderr_text_str)
 
     def init_io(self):
         if sys.platform not in {'win32', 'cli'}:
             return
 
         self.enable_win_unicode_console()
 
         import colorama
         colorama.init()
 
         # For some reason we make these wrappers around stdout/stderr.
         # For now, we need to reset them so all output gets coloured.
         # https://github.com/ipython/ipython/issues/8669
         # io.std* are deprecated, but don't show our own deprecation warnings
         # during initialization of the deprecated API.
         with warnings.catch_warnings():
             warnings.simplefilter('ignore', DeprecationWarning)
             io.stdout = io.IOStream(sys.stdout)
             io.stderr = io.IOStream(sys.stderr)
 
     def init_magics(self):
         super(TerminalInteractiveShell, self).init_magics()
         self.register_magics(TerminalMagics)
 
     def init_alias(self):
         # The parent class defines aliases that can be safely used with any
         # frontend.
         super(TerminalInteractiveShell, self).init_alias()
 
         # Now define aliases that only make sense on the terminal, because they
         # need direct access to the console in a way that we can't emulate in
         # GUI or web frontend
         if os.name == 'posix':
             for cmd in ['clear', 'more', 'less', 'man']:
                 self.alias_manager.soft_define_alias(cmd, cmd)
 
 
     def __init__(self, *args, **kwargs):
         super(TerminalInteractiveShell, self).__init__(*args, **kwargs)
         self.init_prompt_toolkit_cli()
         self.init_term_title()
         self.keep_running = True
 
         self.debugger_history = InMemoryHistory()
 
     def ask_exit(self):
         self.keep_running = False
 
     rl_next_input = None
 
     def pre_prompt(self):
         if self.rl_next_input:
             self.pt_cli.application.buffer.text = cast_unicode_py2(self.rl_next_input)
             self.rl_next_input = None
 
     def interact(self, display_banner=DISPLAY_BANNER_DEPRECATED):
 
         if display_banner is not DISPLAY_BANNER_DEPRECATED:
             warn('interact `display_banner` argument is deprecated since IPython 5.0. Call `show_banner()` if needed.', DeprecationWarning, stacklevel=2)
 
         self.keep_running = True
         while self.keep_running:
             print(self.separate_in, end='')
 
             try:
                 code = self.prompt_for_code()
             except EOFError:
                 if (not self.confirm_exit) \
                         or self.ask_yes_no('Do you really want to exit ([y]/n)?','y','n'):
                     self.ask_exit()
 
             else:
                 if code:
                     self.run_cell(code, store_history=True)
 
     def mainloop(self, display_banner=DISPLAY_BANNER_DEPRECATED):
         # An extra layer of protection in case someone mashing Ctrl-C breaks
         # out of our internal code.
         if display_banner is not DISPLAY_BANNER_DEPRECATED:
             warn('mainloop `display_banner` argument is deprecated since IPython 5.0. Call `show_banner()` if needed.', DeprecationWarning, stacklevel=2)
         while True:
             try:
                 self.interact()
                 break
             except KeyboardInterrupt:
                 print("\nKeyboardInterrupt escaped interact()\n")
 
     _inputhook = None
     def inputhook(self, context):
         if self._inputhook is not None:
             self._inputhook(context)
 
     def enable_gui(self, gui=None):
         if gui:
             self._inputhook = get_inputhook_func(gui)
         else:
             self._inputhook = None
 
     # Run !system commands directly, not through pipes, so terminal programs
     # work correctly.
     system = InteractiveShell.system_raw
 
     def auto_rewrite_input(self, cmd):
         """Overridden from the parent class to use fancy rewriting prompt"""
         if not self.show_rewritten_input:
             return
 
         tokens = self.prompts.rewrite_prompt_tokens()
         if self.pt_cli:
             self.pt_cli.print_tokens(tokens)
             print(cmd)
         else:
             prompt = ''.join(s for t, s in tokens)
             print(prompt, cmd, sep='')
 
     _prompts_before = None
     def switch_doctest_mode(self, mode):
         """Switch prompts to classic for %doctest_mode"""
         if mode:
             self._prompts_before = self.prompts
             self.prompts = ClassicPrompts(self)
         elif self._prompts_before:
             self.prompts = self._prompts_before
             self._prompts_before = None
         self._update_layout()
 
 
 InteractiveShellABC.register(TerminalInteractiveShell)
 
 if __name__ == '__main__':
     TerminalInteractiveShell.instance().interact()

docs/source/config/details.rst

@@ -1,229 +1,230 b''
 =======================
 Specific config details
 =======================
 
 .. _custom_prompts:
 
 Custom Prompts
 ==============
 
 .. versionchanged:: 5.0
 
 From IPython 5, prompts are produced as a list of Pygments tokens, which are
 tuples of (token_type, text). You can customise prompts by writing a method
 which generates a list of tokens.
 
 There are four kinds of prompt:
 
 * The **in** prompt is shown before the first line of input
   (default like ``In [1]:``).
 * The **continuation** prompt is shown before further lines of input
   (default like ``...:``).
 * The **rewrite** prompt is shown to highlight how special syntax has been
   interpreted (default like ``----->``).
 * The **out** prompt is shown before the result from evaluating the input
   (default like ``Out[1]:``).
 
 Custom prompts are supplied together as a class. If you want to customise only
 some of the prompts, inherit from :class:`IPython.terminal.prompts.Prompts`,
 which defines the defaults. The required interface is like this:
 
 .. class:: MyPrompts(shell)
 
    Prompt style definition. *shell* is a reference to the
    :class:`~.TerminalInteractiveShell` instance.
 
    .. method:: in_prompt_tokens(cli=None)
                continuation_prompt_tokens(self, cli=None, width=None)
                rewrite_prompt_tokens()
                out_prompt_tokens()
 
       Return the respective prompts as lists of ``(token_type, text)`` tuples.
 
       For continuation prompts, *width* is an integer representing the width of
       the prompt area in terminal columns.
 
       *cli*, where used, is the prompt_toolkit ``CommandLineInterface`` instance.
       This is mainly for compatibility with the API prompt_toolkit expects.
 
 Here is an example Prompt class that will show the current working directory
 in the input prompt:
 
 .. code-block:: python
 
     from IPython.terminal.prompts import Prompts, Token
     import os
 
     class MyPrompt(Prompts):
          def in_prompt_tokens(self, cli=None):
              return [(Token, os.getcwd()),
                      (Token.Prompt, ' >>>')]
 
 To set the new prompt, assign it to the ``prompts`` attribute of the IPython
 shell:
 
 .. code-block:: python
 
     In [2]: ip = get_ipython()
        ...: ip.prompts = MyPrompt(ip)
 
     /home/bob >>> # it works
 
 See ``IPython/example/utils/cwd_prompt.py`` for an example of how to write an
 extensions to customise prompts.
 
 Inside IPython or in a startup script, you can use a custom prompts class
 by setting ``get_ipython().prompts`` to an *instance* of the class.
 In configuration, ``TerminalInteractiveShell.prompts_class`` may be set to
 either the class object, or a string of its full importable name.
 
 To include invisible terminal control sequences in a prompt, use
 ``Token.ZeroWidthEscape`` as the token type. Tokens with this type are ignored
 when calculating the width.
 
 Colours in the prompt are determined by the token types and the highlighting
 style; see below for more details. The tokens used in the default prompts are
 ``Prompt``, ``PromptNum``, ``OutPrompt`` and ``OutPromptNum``.
 
 .. _termcolour:
 
 Terminal Colors
 ===============
 
 .. versionchanged:: 5.0
 
 There are two main configuration options controlling colours.
 
 ``InteractiveShell.colors`` sets the colour of tracebacks and object info (the
 output from e.g. ``zip?``). It may also affect other things if the option below
 is set to ``'legacy'``. It has four case-insensitive values:
 ``'nocolor', 'neutral', 'linux', 'lightbg'``. The default is *neutral*, which
 should be legible on either dark or light terminal backgrounds. *linux* is
 optimised for dark backgrounds and *lightbg* for light ones.
 
-``TerminalInteractiveShell.highlighting_style`` determines prompt colours and syntax
-highlighting. It takes the name of a Pygments style as a string, or the special
-value ``'legacy'`` to pick a style in accordance with ``InteractiveShell.colors``.
+``TerminalInteractiveShell.highlighting_style`` determines prompt colours and
+syntax highlighting. It takes the name (as a string) or class (as a subclass of
+``pygments.style.Style``) of a Pygments style, or the special value ``'legacy'``
+to pick a style in accordance with ``InteractiveShell.colors``.
 
 You can see the Pygments styles available on your system by running::
 
     import pygments
     list(pygments.styles.get_all_styles())
 
 Additionally, ``TerminalInteractiveShell.highlighting_style_overrides`` can override
 specific styles in the highlighting. It should be a dictionary mapping Pygments
 token types to strings defining the style. See `Pygments' documentation
 <http://pygments.org/docs/styles/#creating-own-styles>`__ for the language used
 to define styles.
 
 Colors in the pager
 -------------------
 
 On some systems, the default pager has problems with ANSI colour codes.
 To configure your default pager to allow these:
 
 1. Set the environment PAGER variable to ``less``.
 2. Set the environment LESS variable to ``-r`` (plus any other options
    you always want to pass to less by default). This tells less to
    properly interpret control sequences, which is how color
    information is given to your terminal.
 
 .. _editors:
 
 Editor configuration
 ====================
 
 IPython can integrate with text editors in a number of different ways:
 
 * Editors (such as `(X)Emacs`_, vim_ and TextMate_) can
   send code to IPython for execution.
 
 * IPython's ``%edit`` magic command can open an editor of choice to edit
   a code block.
 
 The %edit command (and its alias %ed) will invoke the editor set in your
 environment as :envvar:`EDITOR`. If this variable is not set, it will default
 to vi under Linux/Unix and to notepad under Windows. You may want to set this
 variable properly and to a lightweight editor which doesn't take too long to
 start (that is, something other than a new instance of Emacs). This way you
 can edit multi-line code quickly and with the power of a real editor right
 inside IPython.
 
 You can also control the editor by setting :attr:`TerminalInteractiveShell.editor`
 in :file:`ipython_config.py`.
 
 Vim
 ---
 
 Paul Ivanov's `vim-ipython <https://github.com/ivanov/vim-ipython>`_ provides
 powerful IPython integration for vim.
 
 .. _emacs:
 
 (X)Emacs
 --------
 
 If you are a dedicated Emacs user, and want to use Emacs when IPython's
 ``%edit`` magic command is called you should set up the Emacs server so that
 new requests are handled by the original process. This means that almost no
 time is spent in handling the request (assuming an Emacs process is already
 running). For this to work, you need to set your EDITOR environment variable
 to 'emacsclient'. The code below, supplied by Francois Pinard, can then be
 used in your :file:`.emacs` file to enable the server:
 
 .. code-block:: common-lisp
 
     (defvar server-buffer-clients)
     (when (and (fboundp 'server-start) (string-equal (getenv "TERM") 'xterm))
       (server-start)
       (defun fp-kill-server-with-buffer-routine ()
         (and server-buffer-clients (server-done)))
       (add-hook 'kill-buffer-hook 'fp-kill-server-with-buffer-routine))
 
 Thanks to the work of Alexander Schmolck and Prabhu Ramachandran,
 currently (X)Emacs and IPython get along very well in other ways.
 
 With (X)EMacs >= 24, You can enable IPython in python-mode with:
 
 .. code-block:: common-lisp
 
     (require 'python)
     (setq python-shell-interpreter "ipython")
 
 .. _`(X)Emacs`: http://www.gnu.org/software/emacs/
 .. _TextMate: http://macromates.com/
 .. _vim: http://www.vim.org/
 
 .. _custom_keyboard_shortcuts
 
 Keyboard Shortcuts
 ==================
 
 .. versionchanged:: 5.0
 
 You can customise keyboard shortcuts for terminal IPython. Put code like this in
 a :ref:`startup file <startup_files>`::
 
     from IPython import get_ipython
     from prompt_toolkit.enums import DEFAULT_BUFFER
     from prompt_toolkit.keys import Keys
     from prompt_toolkit.filters import HasFocus, HasSelection, ViInsertMode, EmacsInsertMode
 
     ip = get_ipython()
     insert_mode = ViInsertMode() | EmacsInsertMode()
 
     def insert_unexpected(event):
         buf = event.current_buffer
         buf.insert_text('The Spanish Inquisition')
 
     # Register the shortcut if IPython is using prompt_toolkit
     if getattr(ip, 'pt_cli'):
         registry = ip.pt_cli.application.key_bindings_registry
         registry.add_binding(Keys.ControlN,
                          filter=(HasFocus(DEFAULT_BUFFER)
                                  & ~HasSelection()
                                  & insert_mode))(insert_unexpected)
 
 For more information on filters and what you can do with the ``event`` object,
 `see the prompt_toolkit docs
 <http://python-prompt-toolkit.readthedocs.io/en/latest/pages/building_prompts.html#adding-custom-key-bindings>`__.